Herein,we demonstrate an optical thermometer based on single Eu^(2+)doped Ca_(9)Mg_(1.5)(PO_4)_7 phosphors,which were prepared by traditional solid-state reaction technique under a reduction atmosphere.Considerations ...Herein,we demonstrate an optical thermometer based on single Eu^(2+)doped Ca_(9)Mg_(1.5)(PO_4)_7 phosphors,which were prepared by traditional solid-state reaction technique under a reduction atmosphere.Considerations on the bond length obtained by the crystal structure refinement and the dependent photoluminescence performances allow to assign the two distinct emission bands to Eu^(2+)ions occupied Cal-Ca3 and Mg2 sites.Moreover,the blue and red emitting bands perfectly match with the photosynthetic action spectrum,which can enhance the indoor plant photosynthesis.The optimal doping content of Eu^(2+)ions in this Ca_(9)Mg_(1.5)(PO_(4))_(7)system is 3 mol%.The corresponding concentration quenching effect is verified as dipole-dipole interaction with the critical distance of 3.315 nm.Furthermore,by exploiting the fluorescence intensity technique,the optical thermal resistance properties of Ca_(9)Mg_(1.5)(PO_4)_7:Eu^(2+)are identified based on the temperature dependent emission spectra in a range of 303-523 K.In detail,the maximum absolute and relative sensitivity S_(a)and S_(r)of Ca_9Mg_(1.5)(PO_(4))_(7):Eu^(2+)thermometer are as high as 0.637%/K and 0.3155 K^(-1),respectively.Consequently,the Eu^(2+)doped Ca_(9)Mg_(1.5)(PO_(4))_(7)phosphors establish a bifunctional platfo rm for both optical the rmometer and plant growth lighting via multi-site occupancies.展开更多
The challenges and opportunities for developing sustainable plant factories with artificial lighting(PFALs)are discussed.After examining the production cost and productivity of existing PFALs in Japan,the possibility ...The challenges and opportunities for developing sustainable plant factories with artificial lighting(PFALs)are discussed.After examining the production cost and productivity of existing PFALs in Japan,the possibility of introducing a relatively new concept and methodology for considerably improving productivity are discussed in relation to environmental controllability and resource use efficiencies.The fundamental and potential characteristics of ideal or next-generation PFALs(n-PFALs)are then discussed with some suggestions for actualizing n-PFALs.Finally,perspectives of the n-PFALs and technologies to be integrated into the n-PFALs are presented in relation to the Sustainable Development Goals(SDGs)to be achieved by 2030.展开更多
Red plus blue light-emitting diodes(LEDs)are commonly applied in plant factories with artificial lighting due to photosynthetic pigments,which absorb strongly in red and blue light regions of the spectrum.However,plan...Red plus blue light-emitting diodes(LEDs)are commonly applied in plant factories with artificial lighting due to photosynthetic pigments,which absorb strongly in red and blue light regions of the spectrum.However,plants grown under natural environment are used to utilizing broad-wide spectrum by long-term evolution.In order to examine the effects of addition light added in red plus blue LEDs or white LEDs,green and purple leaf lettuces(Lactuca sativa L.cv.Lvdie and Ziya)were hydroponically cultivated for 20 days under white LEDs,white plus red LEDs,red plus blue LEDs,and red plus blue LEDs supplemented with ultraviolet,green or far-red light,respectively.The results indicated that the addition of far-red light in red plus blue LEDs increased leaf fresh and dry weights of green leaf lettuce by 28%and 34%,respectively.Addition of ultraviolet light did not induce any differences in growth and energy use efficiency in both lettuce cultivars,while supplementing green light with red plus blue LEDs reduced the vitamin C content of green leaf lettuce by 44%and anthocyanin content of purple leaf lettuce by 30%compared with red plus blue LEDs,respectively.Spectral absorbencies of purple leaf lettuce grown under red plus blue LEDs supplemented with green light were lower in green light region compared with those grown under red plus blue LEDs,which was associated with anthocyanin contents.White plus red LEDs significantly increased leaf fresh and dry weights of purple leaf lettuce by 25%,and no significant differences were observed in vitamin C and nitrate contents compared with white LEDs.Fresh weight,light and electrical energy use efficiencies of hydroponic green and purple leaf lettuces grown under white plus red LEDs were higher or no significant differences compared with those grown under red plus blue LEDs.In conclusion,white plus red LEDs were suggested to substitute for red plus blue LEDs in hydroponic lettuce(cv.Lvdie and Ziya)production in plant factories with artificial lighting.展开更多
基金the National Natural Science Foundation of China(52104272)the Fundamental Research Founds for the Central Universities(2652020020)the Program National Key R&D Program of China(2021YFC1910602-01)。
文摘Herein,we demonstrate an optical thermometer based on single Eu^(2+)doped Ca_(9)Mg_(1.5)(PO_4)_7 phosphors,which were prepared by traditional solid-state reaction technique under a reduction atmosphere.Considerations on the bond length obtained by the crystal structure refinement and the dependent photoluminescence performances allow to assign the two distinct emission bands to Eu^(2+)ions occupied Cal-Ca3 and Mg2 sites.Moreover,the blue and red emitting bands perfectly match with the photosynthetic action spectrum,which can enhance the indoor plant photosynthesis.The optimal doping content of Eu^(2+)ions in this Ca_(9)Mg_(1.5)(PO_(4))_(7)system is 3 mol%.The corresponding concentration quenching effect is verified as dipole-dipole interaction with the critical distance of 3.315 nm.Furthermore,by exploiting the fluorescence intensity technique,the optical thermal resistance properties of Ca_(9)Mg_(1.5)(PO_4)_7:Eu^(2+)are identified based on the temperature dependent emission spectra in a range of 303-523 K.In detail,the maximum absolute and relative sensitivity S_(a)and S_(r)of Ca_9Mg_(1.5)(PO_(4))_(7):Eu^(2+)thermometer are as high as 0.637%/K and 0.3155 K^(-1),respectively.Consequently,the Eu^(2+)doped Ca_(9)Mg_(1.5)(PO_(4))_(7)phosphors establish a bifunctional platfo rm for both optical the rmometer and plant growth lighting via multi-site occupancies.
文摘The challenges and opportunities for developing sustainable plant factories with artificial lighting(PFALs)are discussed.After examining the production cost and productivity of existing PFALs in Japan,the possibility of introducing a relatively new concept and methodology for considerably improving productivity are discussed in relation to environmental controllability and resource use efficiencies.The fundamental and potential characteristics of ideal or next-generation PFALs(n-PFALs)are then discussed with some suggestions for actualizing n-PFALs.Finally,perspectives of the n-PFALs and technologies to be integrated into the n-PFALs are presented in relation to the Sustainable Development Goals(SDGs)to be achieved by 2030.
基金This work was supported by the National Key Research and Development Program of China(2017YFB0403901)This manuscript was presented at 2019 International Symposium on Environment Control Technology for Value-added Plant Production hold in Beijing from Aug.27-29,2019.
文摘Red plus blue light-emitting diodes(LEDs)are commonly applied in plant factories with artificial lighting due to photosynthetic pigments,which absorb strongly in red and blue light regions of the spectrum.However,plants grown under natural environment are used to utilizing broad-wide spectrum by long-term evolution.In order to examine the effects of addition light added in red plus blue LEDs or white LEDs,green and purple leaf lettuces(Lactuca sativa L.cv.Lvdie and Ziya)were hydroponically cultivated for 20 days under white LEDs,white plus red LEDs,red plus blue LEDs,and red plus blue LEDs supplemented with ultraviolet,green or far-red light,respectively.The results indicated that the addition of far-red light in red plus blue LEDs increased leaf fresh and dry weights of green leaf lettuce by 28%and 34%,respectively.Addition of ultraviolet light did not induce any differences in growth and energy use efficiency in both lettuce cultivars,while supplementing green light with red plus blue LEDs reduced the vitamin C content of green leaf lettuce by 44%and anthocyanin content of purple leaf lettuce by 30%compared with red plus blue LEDs,respectively.Spectral absorbencies of purple leaf lettuce grown under red plus blue LEDs supplemented with green light were lower in green light region compared with those grown under red plus blue LEDs,which was associated with anthocyanin contents.White plus red LEDs significantly increased leaf fresh and dry weights of purple leaf lettuce by 25%,and no significant differences were observed in vitamin C and nitrate contents compared with white LEDs.Fresh weight,light and electrical energy use efficiencies of hydroponic green and purple leaf lettuces grown under white plus red LEDs were higher or no significant differences compared with those grown under red plus blue LEDs.In conclusion,white plus red LEDs were suggested to substitute for red plus blue LEDs in hydroponic lettuce(cv.Lvdie and Ziya)production in plant factories with artificial lighting.
